The install of the way you show me ¿is it for loss of service?,
As you show me would be:
1. - Passive Node: install SP2 CU1
2. - Balancing cluster with instances.
3. - Check that the passive node instances are in: 10.50.4260
4. - Active Node: Installing SP2 CU1
5. - Balancing the active node.
6. - Check that the active node instances are in: 10.50.4260
Is it right?